Low-modulus polypropylene (LMPP) with controlled stereoregularity showed elastic recovery. To understand the underlying mechanism, changes in the morphology of LMPP under cyclic uniaxial elongation were investigated using in situ SAXS and WAXD. During the first cycle, the undulating structure of the crystal lamellae is large, and fragmentation of the lamellae occurs. On the other hand, during the second cycle, the little fragmentation of the lamellae occurs and that only the lamellae were rotating under elongation. Based on these results, lamella fragmentation has a significant effect on the elastic-recovery rate.
- Shotaro Nishitsuji
- Yuki Watanabe
- Mikihito Takenaka